A thin film transistor liquid crystal display (TFT-LCD) is being developed towards large size and high resolution, and the requirement of customers for visual perception of a display screen is increasingly high. Generally, the quality of the TFT-LCD product is monitored by means of automated optical inspection (AOI) equipment. However, vibration generally appears during operation of the AOI equipment, so that the definition of images taken by a camera is reduced, thus affecting the inspection result.
FIG. 1 is a schematic diagram showing distribution of RGB sub-pixels of a color filter in the prior art. Black matrixes (BM) 12 are arranged on a substrate 11, and red sub-pixels 13a, green sub-pixels 13b and blue sub-pixels 13c are arranged between the black matrixes 12 at intervals. Generally, the width D of each black matrix is used as a critical dimension (CD). During the process of manufacturing TFT-LCD, the RGB sub-pixels will be overlapped with the black matrixes 12, so as to form overlays 14.
The critical dimension CD and overlay width of the TFT-LCD product are measured through the AOI equipment in the production process to inspect the quality of the product. Generally, the AOI equipment vibrates in operation, so that the definition of a scanned image is reduced. For example, the critical dimension and the overlays are fuzzy, and the margin thereof is unclear. As a result, the measurement result is inaccurate, and even misjudgment may be caused. FIG. 2 is a schematic diagram of a fuzzy overlay in a scanned image due to vibration. As shown in FIG. 2, the measured width L2 of the overlay is smaller than the width L1 of a normal overlay.
At present, a method for reducing the vibration of the AOI equipment is to perform anti-vibration treatment on a floor below a machine, or transform a rolling device of a substrate supporting body of the machine into a platform. Further, an air floatation function may be incorporated into a base of the platform, so as to reduce substrate vibration caused by ambient vibration.
Based on the above-mentioned conditions, however, an improved AOI image processing method is urgently needed to solve the technical problem that the definition of a scanned image is reduced due to equipment vibration.